Newsademic British English edition 260

e n g u in
 
n u m b e r s
Researchers from Australia have 
been studying Adelie penguins in 
Antarctica. They believe that the 
number o f these penguins in East

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26th November 2015 
N e w s a d e m ic .co m ™
 - British English edition 
page 
7
Antarctica has increased 135-fold 
over the last 14,000 years. Their 
study suggests that warming tem ­
peratures are the reason for this big 
increase in numbers.
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Adelie p enguins in Antarctica (Jason Auch)
The last Ice Age (or glacial pe­
riod) ended around 11,500 years 
ago. M ost scientists now believe 
that human activity over the last 
150 years is causing average world 
temperatures to rise. This warming, 
they say, is causing the climate to 
change in some parts o f the world. 
The human activity is mainly burn­
ing fossil fuels, or oil, gas and coal. 
This creates carbon dioxide (CO2). 
The scientists say that this extra CO2 
in the atmosphere is trapping more 
o f the Sun’s heat.
Antarctica is almost twice as big 
as Australia. It is often divided into 
East Antarctica and West Antarc­
tica. They are separated by a moun­
tain range called the Transantarctic 
Mountains. East Antarctica is about 
two-thirds o f the continent. The re­
searchers say that this part o f Ant­
arctica is now home to around 1.14 
million breeding pairs o f Adelie 
penguins. This is about 30% o f their 
total population.
There are many different penguin 
species. Even though they cannot 
fly, penguins are birds. Apart from 
those kept in zoos, all penguins live 
in the southern hemisphere. Yet 
only Adelie and Emperor penguins 
breed in Antarctica. Emperors are 
the largest penguins. They grow to a
height o f 122 centimetres (48 inch­
es). Adelie penguins are about 70 
centimetres (27.5 inches) tall.
Adelie penguins get their name 
from a French sea captain and ex­
plorer called Jules Dumont d ’Urville 
(1790 - 1842). He landed on the 
coast o f Antarctica in 1840. The cap­
tain named this part o f the continent 
Adelie Land 
(Terre Adelie).
Adelie 
was his w ife’s name. Later, the pen­
guins were named after Adelie Land.
Adelie penguins live in large 
groups called colonies. They make 
their nests on the land. (Emperor 
penguins nest on sea ice.) Adelie 
penguin nests are made from peb­
bles, or small stones. The birds 
usually return to the same place 
each summer to breed. Their nest­
ing grounds are known as rooker­
ies. Some rookeries have been used 
for thousands o f years. To get to 
the land, the penguins must cross 
any sea ice that blocks the way. On 
ice and snow, Adelie penguins can 
move quickly by sliding, or tobog­
ganing, on their stomachs.
The females lay two eggs. Both 
have normally hatched after 40 
days. The male and female look af­
ter the chicks. They take turns to go 
back to the sea. There, they catch 
and swallow tiny shrimp-like crea­
tures called krill. Back at the nest, 
the krill are regurgitated, or brought 
back up to the mouth, and fed to 
the chicks.
If there is not much sea ice, the 
penguins can get to the sea eas­
ily, catch some krill and return. 
Sometimes the sea ice around the 
coast can stretch for 20 kilometres 
or more. This means that the adult 
penguins have a long way to travel. 
If this journey takes too long, the 
chicks can die from a lack o f food.
Warming temperatures mean that 
some Antarctic sea ice is shrinking.
However, the researchers say that 
this is not the main reason for the 
increase in Adelie penguin num­
bers. M ost o f Antarctica is covered 
in a thick ice sheet. Since the end of 
the last Ice Age, this ice sheet has 
been slowly shrinking. As more 
land around the coast is exposed, 
there are more nesting sites. The re­
searchers believe that more nesting 
sites are the reason for the penguins’ 
population growth.
Adelie penguin colony at a rookery in Antarctica
The researchers say that as long 
as the ice continues to shrink (and 
there are plenty o f krill), the number 
o f Adelie penguins is likely to keep 
rising. □
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